If you are going to be on a treadmill while wearing heavy leg irons, it is important to make sure that your ankles are properly protected with a nice pair of boots. There are several styles of boots to choose from at Mr S — these are modeled in pictures from a while back of one of Richard Hunter’s prisoners:
To see more boots, visit Mr S
Iron restraints from Mr S here
More Bondage / BDSM gear from Mr S here